1) Field of the Invention
The present invention relates to an artificial insemination device for animals, more particularly, a simple device that is easy and convenient to use and allows animal semen to reach the two ducts to uterine horns or the uterus swiftly and smoothly, thereby improving the success rate of artificial insemination and effectively saving the amount of semen needed. The invention herein requires minimal amounts of insemination semen and offers economic benefit. It also renders artificial insemination safer, more hygienic, and more humane.
2) Description of the Prior Art
The assembly and operation of conventional artificial insemination device for animals as shown in FIG. 1 and FIG. 2, typically comprises a plastic catheter tube 10 of certain hardness and a nozzle 20 made of softer material installed protrusively on the front end of catheter tube 10. When artificial insemination is carried out, the catheter tube 10 and nozzle 20 are inserted along the vagina 11 of female animal body 1 until the nozzle 20 at the front penetrates into cervical tract 12. Subsequently, the insertion tube 31 of the semen dispenser (bag or syringe) 30 containing the animal semen is inserted into the rear end of catheter tube 10, and as the operator continuously squeezes the semen dispenser (bag or syringe) 30, the semen contained therein is ejected into the cervical tract 12 through the nozzle 20 of catheter tube 10, where the uterus 13 contracts to draw in semen from cervical tract 12. Although the configuration and operation of such artificial insemination device achieve the purpose of artificial insemination in animals effectively, there are some drawbacks:
1. After the catheter tube 10 penetrates the vagina 11 of female animal body 1, the nozzle 20 at the front is pushed approximately to the position of first cervical ring 121 of cervical tract 12, but there remains considerable distance between the first cervical ring 121 and the uterus. Although the contraction of uterus 13 could draw in the semen from cervical tract 12, a large amount of semen ejected from the nozzle 20 initially accumulates at the position of first cervical ring 121 and cannot instantly flow into the uterus 13. What happens most frequently is that the semen accumulated at the first cervical ring 121 often backflows outside the vaginal orifice 111. As such, not only semen is wasted, the amount of semen that flows into the uterus 13 is proportionately lessened, hence decreasing the probability of successful insemination.
2. In response to the problem of semen backflow, operators commonly dilute the semen fluid many folds (typically 5 cc is diluted into 50-120 cc) and enlarge the inner diameter of catheter tube to accommodate and provide more semen fluid for insemination. But the massive dilution of semen fluid apparently reduces the rate of fertilization and the number of fetus, while using more semen leads to waste directly.
3. As described above, the semen in catheter tube 10 is directly released from the nozzle 20, and when nozzle 20 penetrates the cervical tract 12 from outside the female animal body 1, the accidental admittance of contaminants from outside the body or the vagina 11 is difficult to avoid as the semen flows into the uterus 13. As such, the risk of bacteria infection and inflammation of the vagina, cervical tract, and even the uterus of the animal during artificial insemination is high and, at the same time, the safety of fetus carried in the uterus 13 is jeopardized.
4. To improve the success rate and safety of artificial insemination, the operation of artificial insemination requires professional personnel (such as veterinarians or specialized technical personnel) and, as such, to big animal farms (such as pig farmers), it incurs heavy economic burden and demands considerable professional manpower.
5. After the operator utilizes the catheter tube 10 and nozzle 20 to penetrate the vagina 11 and cervical tract 12 of female animal body 1, he has to use one hand to hold the rear end of catheter tube 10 and the other hand to grip and squeeze the semen dispenser 30, which is apparently more troublesome, inconvenient, cumbersome, and time consuming in operation.
To render animal artificial insemination process more efficient and humane, some operators would use accessory devices. As shown in FIG. 3, such devices include an AI Buddy 40, an elastic saddle-like apparatus resembling the two front legs of an animal, wherein a connector 50 with open posterior is installed at the rear end of catheter tube 10, with a positioning strap 41 disposed between the AI Buddy 40 and the connector 50; as such, during the artificial insemination procedure, the operator straddles the AI Buddy 40 over the back of the female animal 1 such that the female animal feels that a male animal has mounted with its two front legs, a guide bush 60 is then placed at the vaginal orifice 111 of female animal body 1 and after the catheter tube 10 and nozzle 20 penetrate the vagina 11 and reaches the cervical tract 12 through the guide bush 60, the rear end of catheter tube 10 is flexed upward and directly secured by the positioning strap 41 connected to the AI Buddy 40; following the ingress of a semen dispenser 30 insertion tube 31 into the connector 50, the operator only has to squeeze the semen dispenser 30. In such approaches, the operator needs to use both hands at the same time, one for grasping the catheter tube 10 and one for squeezing the semen dispenser 30, a procedure that is troublesome and time consuming, but nevertheless an effective improvement. However, existent shortcomings that have not been improved include semen backflow that wastes semen, which is uneconomical and lowers insemination success rate; the easy inflow of contaminants from the outside of the female animal body into the vagina, cervical tract, and uterus that endanger the health of the female animal and fetus carried in the uterus; and the requiring of specialized personnel for operation, which is uneconomical and involves additional manpower.
To increase the success rate of artificial insemination, an improved artificial insemination device for animals as shown in FIG. 4 and FIG. 5 (U.S. Pat. No. 5,899,848) has been disclosed, which features a balloon 16 attached to nozzle 20 of catheter tube 10. The balloon 16 is folded or tucked completely within the forward end of passage of nozzle 20 with a plurality of perforations 29 formed within the periphery of balloon. When semen dispenser is inserted into nozzle 20 of catheter tube 10, the balloon 16 is inflated by the semen forced therein, and the semen is subsequently expelled through the perforations 29 due to the uterine contractions acting upon the balloon 16 at cervical tract. Undeniably, the device just mentioned is an improvement over conventional artificial insemination devices that have the drawbacks of massive backflow of semen and easily bringing contaminants from outside of female animal body into the vagina, cervical tract and even uterus, hence endangering the health of animal and fetus. But given that after nozzle 20 of catheter tube 10 is extended inward to the position of first cervical ring of cervical tract, the balloon 16 in inflated shape that is exposed under the force of semen merely reaches the forward portion of passage of nozzle 20, still around the first cervical ring. Under the circumstance that there remains considerable distance between the inflated balloon 16 that carries semen fluid and the uterus, the semen expelled under the action of uterine contraction is unable to reach uterus swiftly and efficiently and some would backflow, resulting in waste. To make sure more semen enters uterus, the inner diameter of catheter tube 10 has to be made larger to accommodate more semen, which does not improve the uneconomical use of semen seen in conventional artificial insemination devices.
Referring to FIG. 6 and FIG. 7, another artificial insemination apparatus for animals is disclosed (U.S. Pat. No. 6,526,917), wherein the front end opening 421 of catheter tube 420 is inserted into a sheath-like membrane 410 and the leading edge 412 of membrane 410 is snapped into a positioning ring 422 of catheter tube 420. Subsequently, nozzle 440 is inserted into the front end of catheter tube 420 to immobilize membrane 410. After nozzle 440 is inserted into the front end of catheter tube 420, the various components including the member 410 sandwiched between nozzle 440 and the catheter tube 420 can be further secured to each other by being sonically welded or heat staked. The object of such artificial insemination assembly is to cause the tip 411 of sheath-like membrane 410 to begin unfolding in an inside-out manner not unlike removing one's sock by pulling from the open end when semen is squeezed into the rear end of catheter tube 420 and enters the uterus along the cervical tract where semen is ejected from the opening of tip 411 to enhance the efficiency of insemination, prevent the entry of contaminants into the uterus, and prevent the backflow of semen. Such artificial insemination apparatus is more effective in comparison with prior art. But it still has some drawbacks in actual implementation:
1. Given that membrane 410 is inserted from the opening of catheter tube 420 and secured to nozzle 440 via a leading edge 412, the tip 411 of membrane, when squeezed inside-out under the pressure of semen, must pass through the pathway B (FIG. 6) of nozzle 440 before entering the cervical tract of animal. Thus in order for membrane 410 to enter the uterus of animal, it must have certain length. As we know, the longer the membrane, greater squeeze force to expose it outside the nozzle is required, rendering the whole operation more troublesome. In particular when the semen dispenser is in bag shape, the force generated from squeeze is not as much as that of bottle or syringe, which construes a limitation in implementation.
2. Given that the leading edge 412 of membrane 410 is snapped into the positioning ring 422 of catheter tube 420, membrane 410 is tightly attached to the periphery of tube 420 under certain tension, and subsequently nozzle 440 is tightly conjoined to the periphery of membrane 410. What happens most frequently is that when the membrane 410 under tension is pushed by the exertion of nozzle 440, perforation tends to occur around the edge of front end of catheter tube 420 (shown as C in FIG. 6). In such event, when semen is squeezed into catheter tube 420, the perforation would cause air leakage, which keeps membrane 410 from being squeezed out quickly and smoothly, thereby resulting in poor execution or even the failure of artificial insemination.
3. As perforation C on membrane 410 is totally covered by nozzle 440, the quality of the apparatus becomes uncertain since quality control inspection is difficult to carry out. Similarly the performance of the apparatus also becomes questionable.
4. Given that membrane 410 is inserted into catheter tube 420 from its opening 421, the inner diameter of catheter tube 420 (i.e. the hollow space 424) must be bigger. But bigger tube directly increases the consumption of semen, the same as in prior art. Such apparatus apparently does not offer the economic benefit of saving the usage of semen.
5. To prevent trauma to the animal during artificial insemination, the nozzle is usually made of elastomeric material. If the force used is improper or the animal does not stay still during artificial insemination, the front part of nozzle is prone to deformation or bend which might block the semen pathway. Under the circumstances, it is likely that the membrane 410 disposed inside catheter tube 420 will not extend under pressure to achieve artificial insemination.